1. Field of the Invention
The present invention relates to a magnetic recording/reproducing apparatus, and more particularly, to an idler device of a magnetic recording/reproducing apparatus in which an idler gear is selectively rotated to be in contact with a supply reel according to a rotational direction of an idler gear.
2. Description of the Background Art
FIG. 1 illustrates a tape travelling structure of a general magnetic recording/reproducing apparatus.
As shown in FIG. 1, a supply reel driving body 1 and a winding reel driving body 21 are installed to drive a supply reel (not shown) and a winding reel (not shown) of a tape cassette (not shown) at one side of a main chassis.
A plurality of posts and guide rollers are installed on the main chassis (C) to guide travelling of a tape (T) released from a tape cassette.
A tension post 3 for controlling a tensile force of a travelling tape (T) is installed at a tension arm 4.
The tension arm 4 is rotated at a predetermined angle according to the tension of the tape (T) on the main chassis (C) centering around a shaft pin 2, for which the tension arm 4 is elastically supported by a spring 5.
The tape (T) having passed the tension post 3 is guided by a guide post 6 and transmitted to a full width erasing head 7.
The full width erasing head 7 removes in advance a signal which has been recorded on the tape in a recording mode.
An inertia roller is installed at a position past the full width erasing head 7 to guide the travelling of the tape (T).
Next, the tape (T) is guided by guide posts 10 and 11 of the supplying and winding side which are moved along loading paths formed at both sides of a rotational head drum 9.
The guide posts 10 and 11 draws the tape (T) from the inside of the tape cassette, the position indicated in a dotted line as shown in FIG. 1, so as to be wound and traveled.
A supply slant post 12 and a winding slant post 13 are provided next to the guide posts 10 and 11 toward the rotational head drum 9, so as to guide the traveling of the tape (T).
The guide posts 10 and 11 and the slant posts 12 and 13 are installed on a supply and winding slant bases 14 and 15 and moved along the loading path.
As shown in FIG. 1, the rotational head drum 9, on which the tape (T) is wound and traveled, is provided with a rotational head (not shown) for reading a signal recorded on the tape (T) or recording a signal.
The tape (T) passes the rotational head drum 9 and the slant post 13 and the guide post 11 of the winding side and then passes the audio control head 16. The audio control head 16 performs deleting, recording and reproducing of an audio signal, and recording and reproducing a control signal.
A guide post 17 is provided on the main chassis (C) at an adjacent location of the audio control head 16 to control the traveling height of the tape (T).
A capstan shaft 18 for providing a traveling force to the tape (T) is installed at a position passing the guide post 17. The capstan shaft 18 is an output shaft of a capstan motor (not shown) installed at the opposite face of the main chassis (C), and a traveling direction of the tape (T) is determined depending on the rotational direction of the capstan motor.
A pinch roller 19 is installed selectively tightly-attached to the capstan shaft 18 to provide a force for pulling the tape (T).
A winding post 20 is provided at an adjacent location of the pinch roller 19 and the capstan shaft 18. A winding arm (not shown) is installed and moved at the winding post 20.
Between the supply reel driving body 1 and the winding reel driving body 21, a clutch assembly 22 is installed to drive the supply reel or the winding reel at a certain torque regardless of the amount of the tape (T) wound on the supply reel or the winding reel upon receipt of a driving force from the capstan motor.
An idler gear 24 is installed at a front end of an idler arm 25 which is coaxially installed with the clutch assembly 22. The idler gear 24 is selectively connected to either the supply reel driving body 1 or the winding reel driving body 21 for transferring a driving force thereto upon receipt of a driving force from the clutch assembly 22.
A tension brake 27 is installed wound on the supply reel driving body 1 with its both ends fixed at the tension arm 4. The tension brake 27 controls the rotational speed of the supply reel driving body 1 according to the operation of the tension arm 4, thereby controlling a tension of the tape (T).
The construction of the idler unit including the idler arm 25 and the idler gear 24 will now be described with reference to FIG. 2.
First, the idler arm 25 is installed centering around the clutch shaft 22xe2x80x2 installed penetrating the main chassis (C) The idler arm 25 is positioned at an upper surface of the main chassis (C) and the clutch assembly 22 is installed at the lower surface of the main chassis (C). The clutch shaft 22xe2x80x2, the center of the rotation of the clutch assembly 22, is installed penetrating from the lower surface to the upper surface of the main chassis (C) and fixed as a washer 25w is inserted at the end portion of the clutch shaft 22xe2x80x2.
The idler gear 24 is installed at the front end portion of the idler arm 25, so as to be rotatable centering around an idler shaft 24p. 
An idler spring 25s is installed between the idler arm 25 and the idler gear 24. The idler spring 24s supported by the idler gear 24 is mounted on a friction member 24f installed at the idler gear 24.
The idler spring 24s is operated so that the idler arm 25 can be rotated centering around the clutch shaft 22xe2x80x2 according to the rotational direction of the idler gear 24.
That is, according to the rotational direction of the idler gear 24, the idler gear 24 is selectively engaged with the supply reel driving body 1 or the winding reel driving body 21 to transfer the driving force of the capstan motor.
Reference numerals 24g denotes a large gear and 24gxe2x80x2 denotes a small gear.
However, the idler unit of the conventional art has many problems.
That is, first, in installing the idler arm 25 at the upper surface of the main chassis (C), it is to be assembled together with the clutch assembly 22.
Namely, in a state that the clutch assembly 22 is positioned at the lower surface of the main chassis (C) and the idler arm 25 is positioned at the upper surface of the main chassis (C), the washer 25w is to be engaged at the end portion of the clutch shaft 22xe2x80x2. Thus, the assembly working is relatively complicated.
Secondly, for the installation of the idler arm 25, the washer 25w is necessarily used, creating a problem that the parts for the assembly are relatively increased in number, which results in that a production cost is accordingly increased and the number of assembly working is relatively increased.
Thirdly, in stalling the idler gear 24 at the idler arm 25, the idler shaft 24p is to be installed after positioning the idler spring 24s in a state of a provisional assembly between the idler arm 25 and the idler gear 24. Thus, the assembly operation is relatively complicated.
Fourthly, in the assembly process, if the idler spring 24s allowing an elastic force for the idler gear 24 which is rotated between the friction member 24f and the idler arm 25 is not installed at the right position, the idler gear 24 is not properly operated.
Lastly, since the number of parts for operation of the idler gear 24 is relatively many, its production cost is increased and the process number of the assembly working is relatively increased.
Therefore, an object of the present invention is to provide an idler device for a magnetic recording/reproducing apparatus that is capable of minimizing the number of parts and facilitating an assembly working.
Another object of the present invention is to provide an idler device for a magnetic recording/reproducing apparatus that is capable of heightening a reliability in an idle operation.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an idler device for a magnetic recording/reproducing apparatus including a clutch shaft vertically coupled to a main chassis; an idler arm installed rotatable centering around the clutch shaft by having an mounting portion elastically engaged to the clutch shaft in a snap method in the direction of the side of the clutch shaft at one portion; an idler shaft provided at the other portion of the idler arm; an idler gear rotatably installed at the idler arm centering around the idler shaft, for selectively transmitting a driving force according to a rotational direction; and a pressing elastic member supported by an end portion of the idler shaft, for elastically pressing the idler gear in the direction of the idler arm.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the clutch shaft is provided with a supporting portion at its side and the mounting portion of the idler arm is supported by being coupled between the main chassis and the supporting portion of the clutch shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, a protrusion bar is formed at the end portion of the idler shaft to support the pressing elastic member, and the pressing elastic member is supported by the protrusion bar and made of a disk-shaped plate spring providing an elastic force to the idler gear.
To achieve the above objects, there is also provided an idler device for a magnetic recording/reproducing apparatus including: a rotational central shaft vertically coupled to a main chassis; and an idler arm having an mounting portion elastically engaged to the rotational central shaft in a snap method at the side of the rotational central shaft and an idler gear installed at the opposite of the mounting portion, for selectively transmitting a driving force according to a rotational direction.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the rotational central shaft is a clutch shaft and press-fit to a fixing hole of the main chassis and fixed in a riveting method.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the rotational central shaft includes a supporting portion formed at its circumferential surface, and the mounting portion of the idler arm is supported by being coupled between the main chassis and the supporting portion of the rotational central shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the supporting portion of the rotational central shaft is annularly protruded from the circumference of the rotational central shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the mounting portion of the idler arm includes a shaft insertion portion with one side opened so that the rotational central shaft can be inserted thereinto and a separation preventing unit formed at the opening portion of the shaft insertion portion, for not allowing separation from the rotational central shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the separation preventing unit is elastic legs elastically protruded in the direction of the shaft insertion portion from the opened portion of the mounting portion.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, a front end portion the elastic legs contacts the circumferential face of the rotational central shaft and the space between each elastic leg is smaller than the diameter of the rotational central shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the shaft insertion portion is provided with a semicircular hitching portion closely attached to the rotational central shaft at the portion facing the elastic leg.
To achieve the above objects, there is also provided an idler device of a magnetic recording/reproducing apparatus including: an idler arm installed rotatable centering around a rotational shaft of which one side is fixed at a main chassis; an idler shaft provided at the other side of the idler arm; an idler gear rotatably installed at the idler arm centering around the idler shaft, for selectively transferring a driving force in the rotational direction; and a pressing elastic member supported by the end portion of the idler shaft and elastically pressing the idler gear in the direction of the idler arm.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the idler arm and the idler shaft are integrally formed.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, a protrusion bar is formed at the end portion of the idler shaft, at which the pressing elastic member is installed and supported.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the pressing elastic member is formed as a disk type plate spring.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the pressing elastic member includes a central plate inserted into and supported by the idler shaft, a pressing ring closely attached to the idler gear, and elastic legs connecting the central plate and the pressing ring and having an elastic force.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the central plate has stoppers protruded so as for the central plate to be coupled and supported at the both sides of the idler shaft.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the elastic legs are extended to have a scroll structure at the circumference of the central plate.
In the idler device for a magnetic recording/reproducing apparatus of the present invention, the elastic legs are slantingly connected so as for the central plate and the pressing ring to have a predetermined height difference.
With the idler device for a magnetic recording/reproducing apparatus of the present invention, since the idler arm can be snap-engaged to the clutch shaft and the plate spring is fixed to the idler shaft in a state that the idler gear is inserted into the idler shaft of the idler arm, a workability of the assembly working can be improved and the parts can be simplified in number. Thus, a production unit cost can be reduced.